One winter, when I was walking along the banks of the Daugava, looking at boats covered in snow, I had a thought - create an all-season vehicle, i.e. an amphibian, which could be used in winter.
After much thought, my choice fell on a double device on air cushion . At first I had nothing but a great desire to create such a structure. The technical literature available to me summarized the experience of creating only large hovercraft, but I could not find any data on small devices for recreational and sports purposes, especially since our industry does not produce such hovercraft. So, one could only hope for own strength and experience (my amphibious boat based on the Yantar motorboat was once reported in KYA; see No. 61).
Anticipating that in the future I might have followers, and if the results are positive, industry might also be interested in my device, I decided to design it on the basis of well-developed and commercially available two-stroke engines.
In principle, a hovercraft experiences significantly less stress than a traditional planing boat hull; this allows its design to be made lighter. At the same time, an additional requirement appears: the body of the device must have low aerodynamic drag. This must be taken into account when developing a theoretical drawing.
| Basic data of an amphibious hovercraft | |
|---|---|
| Length, m | 3,70 |
| Width, m | 1,80 |
| Side height, m | 0,60 |
| Air cushion height, m | 0,30 |
| Power lifting installation, l. With. | 12 |
| Traction unit power, l. With. | 25 |
| Payload capacity, kg | 150 |
| Total weight, kg | 120 |
| Speed, km/h | 60 |
| Fuel consumption, l/h | 15 |
| Fuel tank capacity, l | 30 |
1 - steering wheel; 2 - instrument panel; 3 - longitudinal seat; 4 - lifting fan; 5 - fan casing; 6 - traction fans; 7 - fan shaft pulley; 8 - engine pulley; 9 - traction motor; 10 - muffler; 11 - control flaps; 12 - fan shaft; 13 - fan shaft bearings; 14 - windshield; 15 - flexible fencing; 16 - traction fan; 17 - traction fan casing; 18 - lifting motor; 19 - lifting engine muffler;
20 - electric starter; 21 - battery; 22 - fuel tank.
I made the body set from spruce slats with a section of 50x30 and covered it with 4 mm plywood on epoxy glue. I did not cover it with fiberglass, for fear of increasing the weight of the device. To ensure unsinkability, two waterproof bulkheads were installed in each of the side compartments, and the compartments were also filled with foam plastic.
A two-engine power plant scheme has been chosen, i.e. one of the engines works to lift the apparatus, creating overpressure(air cushion) under its bottom, and the second provides movement - creates horizontal thrust. Based on the calculations, the lifting engine should have a power of 10-15 hp. With. Based on the basic data, the engine from the Tula-200 scooter turned out to be the most suitable, but since neither the fastenings nor the bearings satisfied it for design reasons, it had to be cast from aluminum alloy new crankcase. This motor drives a 6-blade fan with a diameter of 600 mm. The total weight of the lifting power unit together with fastenings and electric starter was about 30 kg.
One of the most difficult stages was the manufacture of the skirt - a flexible cushion enclosure that quickly wears out during use. A commercially available tarpaulin fabric with a width of 0.75 m was used. Due to the complex configuration of the joints, about 14 m of such fabric was required. The strip was cut into lengths equal to length sides, with an allowance of quite complex shape joints After giving the required shape, the joints were stitched. The edges of the fabric were attached to the body of the apparatus with 2x20 duralumin strips. To increase wear resistance, I impregnated the installed flexible fencing with rubber glue, to which I added aluminum powder, which gives it an elegant look. This technology makes it possible to restore a flexible fence in the event of an accident and as it wears out, similar to building up a tread car tire. It must be emphasized that the manufacture of flexible fencing not only takes a lot of time, but requires special care and patience.
The hull was assembled and the flexible fencing was installed with the keel up. Then the hull was rolled out and a lifting power unit was installed in a shaft measuring 800x800. The installation control system was installed, and now the most crucial moment came; testing it. Will the calculations be justified, will a relatively low-power engine lift such a device?
Already at medium engine speeds, the amphibian rose with me and hovered at a height of about 30 cm from the ground. The reserve of lifting force turned out to be quite enough for the warmed-up engine to lift even four people at full speed. In the very first minutes of these tests, the features of the device began to emerge. After proper alignment, it moved freely on an air cushion in any direction, even with a small applied force. It seemed as if he was floating on the surface of the water.
The success of the first test of the lifting installation and the hull as a whole gave me inspiration. Having secured Windshield, I started installing the traction power unit. At first it seemed advisable to take advantage of the extensive experience in building and operating snowmobiles and install an engine with a propeller relatively large diameter on the aft deck. However, it should be taken into account that such a “classic” version would significantly increase the center of gravity of such a small device, which would inevitably affect its driving performance and, most importantly, safety. Therefore, I decided to use two traction engines, completely similar to the lifting one, and installed them in the stern of the amphibian, but not on the deck, but along the sides. After I had fabricated and installed a motorcycle-type control drive and installed relatively small-diameter traction propellers (“fans”), the first version of the hovercraft was ready for sea trials.
To transport the amphibian behind a Zhiguli car, a special trailer was made, and in the summer of 1978 I loaded my device onto it and delivered it to a meadow near a lake near Riga. The exciting moment has arrived. Surrounded by friends and curious people, I took the driver's seat, started the lifting engine, and my new boat hung over the meadow. Started both traction engines. As the number of their revolutions increased, the amphibian began to move across the meadow. And then it became clear that many years of experience in driving a car and a motorboat were clearly not enough. All previous skills are no longer suitable. It is necessary to master methods of controlling a hovercraft, which can spin indefinitely in one place, like a spinning top. As the speed increased, the turning radius also increased. Any surface irregularities caused the apparatus to rotate.
Having become comfortable with the controls, I directed the amphibian along the gently sloping shore towards the surface of the lake. Once above the water, the device immediately began to lose speed. The traction engines began to stall one by one, flooded with spray escaping from under the flexible air cushion enclosure. When passing through overgrown areas of the lake, the fans sucked in reeds, and the edges of their blades became discolored. When I turned off the engines and then decided to try to take off from the water, nothing happened: my device was never able to escape from the “hole” formed by the pillow.
All in all, it was a failure. However, the first defeat did not stop me. I came to the conclusion that, given the existing characteristics, the power of the traction system is insufficient for my hovercraft; that is why he could not move forward when starting from the surface of the lake.
During the winter of 1979, I completely redesigned the amphibian, reducing the length of its body to 3.70 m and its width to 1.80 m. I also designed a completely new traction unit, completely protected from splashes and from contact with grass and reeds. To simplify the control of the installation and reduce its weight, one traction motor is used instead of two. The power head of a 25-horsepower Vikhr-M outboard motor with a completely redesigned cooling system was used. The 1.5 liter closed cooling system is filled with antifreeze. The engine torque is transmitted to the fan “propeller” shaft located across the device using two V-belts. Six-bladed fans force air into the chamber, from which it escapes (at the same time cooling the engine) behind the stern through a square nozzle equipped with control flaps. From an aerodynamic point of view, such a traction system is apparently not very perfect, but it is quite reliable, compact and creates a thrust of about 30 kgf, which turned out to be quite sufficient.
In mid-summer 1979, my apparatus was again transported to the same meadow. Having mastered the controls, I directed it towards the lake. This time, once above the water, he continued to move without losing speed, as if on the surface of ice. Easily, without hindrance, overcame shallows and reeds; It was especially pleasant to move over the overgrown areas of the lake; there was not even a foggy trace left. On the straight section, one of the owners with a Vikhr-M engine set off on a parallel course, but soon fell behind.
The described apparatus caused particular surprise among ice fishing enthusiasts when I continued testing the amphibian in winter on ice, which was covered with a layer of snow about 30 cm thick. It was a real expanse on the ice! The speed could be increased to maximum. I didn’t measure it exactly, but the driver’s experience allows me to say that it was approaching 100 km/h. At the same time, the amphibian freely overcame the deep tracks left by the motor guns.
A short film was shot and shown at the Riga television studio, after which I began to receive many requests from those who wanted to build such an amphibious vehicle.
It all started with the fact that I wanted to do some project and involve my grandson in it. I have a big engineering experience behind you, so simple projects I wasn’t looking, and then one day, while watching TV, I saw a boat that was moving due to the propeller. "Cool stuff!" - I thought, and began to scour the Internet in search of at least some information.
We took the motor from an old lawn mower, and bought the layout itself (costs $30). It is good because it requires only one motor, while most similar boats require two engines. From the same company we bought the propeller, propeller hub, air cushion fabric, epoxy resin, fiberglass and screws (they sell them all in one kit). The rest of the materials are quite commonplace and can be purchased at any hardware store. The final budget was a little over $600.
Step 1: Materials
Materials you will need: polystyrene foam, plywood, kit from Universal Hovercraft (~$500). The kit contains all the little things you will need to complete the project: plan, fiberglass, propeller, propeller hub, air cushion fabric, glue, epoxy resin, bushings, etc. As I wrote in the description, all materials cost about $600.
Step 2: Making the frame
We take polystyrene foam (5 cm thick) and cut out a 1.5 by 2 meter rectangle from it. Such dimensions will ensure buoyancy of a weight of ~270 kg. If 270 kg seems not enough, you can take another sheet of the same type and attach it below. We cut out two holes with a jigsaw: one for the incoming air flow and the other for inflating the pillow.
Step 3: Cover with fiberglass
The lower part of the body must be waterproof, for this we cover it with fiberglass and epoxy. In order for everything to dry properly, without unevenness and roughness, you need to get rid of any air bubbles that may arise. For this you can use industrial vacuum cleaner. We cover the fiberglass with a layer of film, then cover it with a blanket. The covering is necessary to prevent the blanket from sticking to the fiber. Then we cover the blanket with another layer of film and glue it to the floor with adhesive tape. We make a small cut, insert the trunk of the vacuum cleaner into it and turn it on. We leave it in this position for a couple of hours, when the procedure is completed, the plastic can be scraped off from the fiberglass without any effort, it will not stick to it.
Step 4: Bottom Case is Ready
The lower part of the body is ready, and now it looks something like the photo.
Step 5: Making the Pipe
The pipe is made of styrofoam, 2.5 cm thick. It is difficult to describe the whole process, but in the plan it is described in detail, we did not have any problems at this stage. Let me just note that the plywood disk is temporary and will be removed in subsequent steps.
Step 6: Motor Holder
The design is not tricky; it is made of plywood and blocks. Placed exactly in the center of the boat hull. Attaches with glue and screws.
Step 7: Propeller
The propeller can be purchased in two forms: ready-made and “semi-finished”. Ready-made ones are usually much more expensive, and buying a semi-finished product can save a lot of money. That's what we did.
The closer the propeller blades are to the edges of the air vent, the more efficiently the latter works. Once you have decided on the gap, you can sand the blades. Once the grinding is completed, it is necessary to balance the blades so that there are no vibrations in the future. If one of the blades weighs more than the other, then the weight needs to be equalized, but not by cutting the ends, or by grinding. Once the balance is found, you can apply a couple of layers of paint to maintain it. For safety, it is advisable to paint the tips of the blades in White color.
Step 8: Air Chamber
The air chamber separates the flow of incoming and outgoing air. Made from 3 mm plywood.
Step 9: Installing the Air Chamber
The air chamber is attached with glue, but you can also use fiberglass; I always prefer to use fiber.
Step 10: Guides
The guides are made of 1 mm plywood. To give them strength, cover them with one layer of fiberglass. It’s not very clear in the photo, but you can still see that both guides are connected together at the bottom with an aluminum strip, this is done so that they work synchronously.
Step 11: Shape the Boat and Add Side Panels
The outline of the shape/contour is made on the bottom, after which it is attached with screws according to the outline wooden plank. 3mm plywood bends well and fits right into the shape we need. Next, we fasten and glue a 2 cm beam along the upper edge of the plywood sides. Add cross beam, and install the handle, which will be the steering wheel. We attach cables to it extending from the guide blades installed earlier. Now you can paint the boat, preferably applying several layers. We chose white; even with prolonged direct sunlight, the body practically does not heat up.
I must say that she swims briskly, and this makes me happy, but it surprised me steering. At medium speeds turns are possible, but at high speed The boat first skids to the side, and then, due to inertia, it moves backwards for some time. Although, after getting used to it a little, I realized that tilting my body in the direction of the turn and slightly slowing down the gas can significantly reduce this effect. It’s difficult to say the exact speed, because there is no speedometer on the boat, but it feels quite good, and there is still a decent wake and waves left behind the boat.
On the day of the test, about 10 people tried the boat, the heaviest weighed about 140 kg, and it withstood it, although of course it was not possible to achieve the speed that was available to us. With a weight of up to 100 kg, the boat moves briskly.
Join the club
learn about the most interesting instructions once a week, share yours and participate in giveaways!
The quality of the road network in our country leaves much to be desired. Construction in some areas is impractical economic reasons. Vehicles operating on different physical principles can cope perfectly with the movement of people and goods in such areas. Do-it-yourself full-size boats in artisanal conditions not to build, but scale models- quite possible.
Vehicles of this type are capable of moving on any relatively flat surface. It could be open field, and a pond, and even a swamp. It is worth noting that on such surfaces, unsuitable for other vehicles, the hovercraft is capable of developing a fairly high speed. The main disadvantage of such transport is the need for large energy costs to create an air cushion and, as a consequence, high consumption fuel.
Physical principles of hovercraft operation
The high cross-country ability of vehicles of this type is ensured by the low specific pressure that it exerts on the surface. This is explained quite simply: the contact area of the vehicle is equal to or even greater than the area of the vehicle itself. In encyclopedic dictionaries, hovercraft are defined as vessels with a dynamically created support thrust.
Large and air-cushioned they hover above the surface at a height of 100 to 150 mm. Air is created in a special device under the body. The machine breaks away from the support and loses mechanical contact with it, as a result of which the resistance to movement becomes minimal. The main energy costs go to maintaining the air cushion and accelerating the device in the horizontal plane.
Drafting a project: choosing a working scheme
To produce a working hovercraft mock-up, it is necessary to select a body design that is effective for the given conditions. Drawings of hovercraft can be found on specialized resources where patents with detailed description different schemes and ways to implement them. Practice shows that one of the most good options for media such as water and solid soil, it is chamber method formation of an air cushion.
Our model will implement a classic two-engine design with one pumping power drive and one pushing one. Small-sized hovercraft made by hand are, in fact, toy copies of large devices. However, they clearly demonstrate the advantages of using such vehicles over others.
Vessel hull manufacturing
When choosing a material for a ship's hull, the main criteria are ease of processing and low hovercraft are classified as amphibious, which means that in the event of an unauthorized stop, flooding will not occur. The hull of the vessel is cut out of plywood (4 mm thick) according to a pre-prepared pattern. A jigsaw is used to perform this operation.
A homemade hovercraft has superstructures that are best made from polystyrene foam to reduce weight. To give them a greater external resemblance to the original, the parts are glued with penoplex and painted on the outside. Cabin glass is made from them transparent plastic, and the remaining parts are cut out of polymers and bent from wire. Maximum detail is the key to resemblance to the prototype.
Air chamber dressing
When making the skirt, dense fabric made of polymer waterproof fiber is used. Cutting is carried out according to the drawing. If you do not have experience transferring sketches onto paper by hand, you can print them on a large-format printer on thick paper and then cut them out with regular scissors. The prepared parts are sewn together, the seams should be double and tight.
Self-made hovercraft rest their hull on the ground before turning on the supercharger engine. The skirt is partially wrinkled and placed underneath. The parts are glued together with waterproof glue, and the joint is closed by the superstructure body. This connection ensures high reliability and makes the installation joints invisible. From polymer materials Other external parts are also made: the propeller diffuser guard and the like.
Power point
The power plant contains two engines: a supercharger and a propulsion engine. The model uses brushless electric motors and two-blade propellers. They are remotely controlled using a special regulator. The power source for the power plant is two batteries with a total capacity of 3000 mAh. Their charge is enough for half an hour of using the model.
Homemade hovercraft are controlled remotely via radio. All system components - radio transmitter, receiver, servos - are factory-made. They are installed, connected and tested in accordance with the instructions. After turning on the power, a test run of the engines is performed with a gradual increase in power until a stable air cushion is formed.
SVP model management
Hovercraft, made by hand, as noted above, have remote control via VHF channel. In practice, it looks like this: the owner has a radio transmitter in his hands. The engines are started by pressing the corresponding button. Speed control and change of direction of movement are made by joystick. The machine is easy to maneuver and maintains its course quite accurately.
Tests have shown that the hovercraft confidently moves on a relatively flat surface: on water and on land with equal ease. The toy will become a favorite entertainment for a child aged 7-8 years with a sufficiently developed fine motor skills fingers
The prototype of the presented amphibious vehicle was an air-cushion vehicle (AVP) called “Aerojeep”, a publication about which was in the magazine. Like the previous device, the new machine is single-engine, single-propeller with distributed air flow. This model is also a three-seater, with the pilot and passengers arranged in a T-shape: the pilot is in the front in the middle, and the passengers are on the sides, in the back. Although nothing prevents the fourth passenger from sitting behind the driver’s back - the length of the seat and the power of the propeller engine are quite enough.
New car, except improved ones technical characteristics, has a number design features and even innovations that increase its operational reliability and survivability - after all, an amphibian is a waterfowl. And I call it a “bird” because it still moves through the air both above water and above land.
Structurally, the new machine consists of four main parts: a fiberglass body, a pneumatic cylinder, a flexible fence (skirt) and a propeller unit.
Talking about new car, you will inevitably have to repeat yourself - after all, the designs are largely similar.
Amphibious Corps identical to the prototype both in size and design - fiberglass, double, three-dimensional, consisting of inner and outer shells. It is worth noting here that the holes in the inner shell in the new device are now located not at the upper edge of the sides, but approximately in the middle between it and the bottom edge, which ensures a faster and more stable creation of an air cushion. The holes themselves are now not oblong, but round, with a diameter of 90 mm. There are about 40 of them and they are located evenly along the sides and front.
Each shell was glued into its own matrix (used from the previous design) from two to three layers of fiberglass (and the bottom from four layers) on a polyester binder. Of course, these resins are inferior to vinyl ester and epoxy resins in terms of adhesion, filtration level, shrinkage, and the release of harmful substances upon drying, but they have undeniable advantage in price - they are much cheaper, which is important. For those who intend to use such resins, let me remind you that the room where the work is carried out must have good ventilation and a temperature of at least +22°C.
1 – segment (set of 60 pcs.); 2 – balloon; 3 – mooring cleat (3 pcs.); 4 – wind visor; 5 – handrail (2 pcs.); 6 – mesh fence propeller; 7 – outer part of the annular channel; 8 – rudder (2 pcs.); 9 – steering wheel control lever; 10 – hatch in the tunnel for access to the fuel tank and battery; 11 – pilot’s seat; 12 – passenger sofa; 13 – engine casing; 14 – oar (2 pcs.); 15 – muffler; 16 – filler (foam); 17 – inner part of the annular channel; 18 – lantern navigation light; 19 – propeller; 20 – propeller hub; 21 – drive toothed belt; 22 – attachment point for the cylinder to the body; 23 – attachment point of the segment to the body; 24 – engine on motor mount; 25 – inner shell of the body; 26 – filler (foam); 27 – outer shell housings; 28 – dividing panel for forced air flow
The matrices were made in advance according to the master model from the same glass mats on the same polyester resin, only the thickness of their walls was larger and amounted to 7-8 mm (for the housing shells - about 4 mm). Before baking elements with work surface the matrix was carefully removed all roughness and burrs, and it was covered three times with wax diluted in turpentine and polished. After this, it was applied to the surface with a spray (or roller) thin layer(up to 0.5 mm) red gelcoat (colored varnish).
After it dried, the process of gluing the shell began using the following technology. First, using a roller, the wax surface of the matrix and one side of the glass mat (with smaller pores) are coated with resin, and then the mat is placed on the matrix and rolled until the air is completely removed from under the layer (if necessary, you can make a small slot in the mat). In the same way, subsequent layers of glass mats are laid to the required thickness (3-4 mm), with the installation, where necessary, of embedded parts (metal and wood). Excess flaps along the edges were trimmed off when gluing “wet”.
A - outer shell;
b – inner shell;
1 – ski (tree);
2 – sub-motor plate (wood)
After making the outer and inner shells separately, they were joined, fastened with clamps and self-tapping screws, and then glued along the perimeter with strips of coated polyester resin the same glass mat 40 -50 mm wide from which the shells themselves were made. After attaching the shells to the edge with petal rivets, a vertical side strip made of 2 mm duralumin strip with a width of at least 35 mm was attached around the perimeter.
Additionally, pieces of resin-impregnated fiberglass should be carefully glued to all corners and places where fasteners are screwed in. The outer shell is covered on top with gelcoat - a polyester resin with acrylic additives and wax, which gives shine and water resistance.
It is worth noting that smaller elements were glued using the same technology (the outer and inner shells were made): the inner and outer shells of the diffuser, steering wheels, engine casing, wind deflector, tunnel and driver's seat. A 12.5 liter gas tank (industrial from Italy) is inserted inside the housing, into the console, before fastening the lower and upper parts of the housings.
inner shell of the housing with air outlets to create an air cushion; above the holes there is a row of cable clips for hooking the ends of the scarf of the skirt segment; two wooden skis glued to the bottom
For those who are just starting to work with fiberglass, I recommend starting to build a boat with these small elements. The total weight of the fiberglass body together with skis and aluminum alloy strip, diffuser and rudders is from 80 to 95 kg.
The space between the shells serves as an air duct around the perimeter of the apparatus from the stern on both sides to the bow. The top and bottom of this space are filled construction foam, which provides optimal cross section air channels and additional buoyancy (and, accordingly, survivability) of the device. The pieces of foam plastic were glued together with the same polyester binder, and they were glued to the shells with strips of fiberglass, also impregnated with resin. Next, from the air channels, the air comes out through evenly spaced holes with a diameter of 90 mm in the outer shell, “rests” on the skirt segments and creates an air cushion under the device.
To protect against damage, a pair of longitudinal skis made of wooden blocks are glued to the bottom of the outer shell of the hull from the outside, and an under-engine wooden plate is glued to the aft part of the cockpit (that is, from the inside).
Balloon. New model The hovercraft has almost twice the displacement (350 - 370 kg) than the previous one. This was achieved by installing an inflatable balloon between the body and the segments of the flexible fence (skirt). The cylinder is glued from a lavsan-based PVC film material Uipuriap, produced in Finland, with a density of 750 g/m 2 according to the shape of the body in plan. The material has been tested on large industrial hovercraft such as Chius, Pegasus, and Mars. To increase survivability, the cylinder can consist of several compartments (in in this case– of the three, each has its own filling valve). The compartments, in turn, can be divided in half lengthwise by longitudinal partitions (but this version of them is still only in the design). With this design, a broken compartment (or even two) will allow you to continue moving along the route, and even more so to get to the shore for repairs. For economical cutting of material, the cylinder is divided into four sections: a bow section and two feed sections. Each section, in turn, is glued together from two parts (halves) of the shell: lower and upper - their patterns are mirrored. In this version of the cylinder, the compartments and sections do not match.
a – outer shell; b – inner shell;
1 – bow section; 2 – side section (2 pcs.); 3 – aft section; 4 – partition (3 pcs.); 5 – valves (3 pcs.); 6 – lyktros; 7 – apron
A “liktros” is glued to the top of the cylinder - a strip of Vinyplan 6545 “Arctic” material folded in half, with a braided nylon cord inserted along the fold, impregnated with “900I” glue. “Liktros” is applied to the side bar, and with the help of plastic bolts the cylinder is attached to an aluminum strip fixed to the body. The same strip (only without the attached cord) is glued to the cylinder and from the bottom in front (“at half past seven”), the so-called “apron” - to which the upper parts of the segments (tongues) of the flexible fence are tied. Later, a rubber bumper bumper was glued to the front of the cylinder.
Soft elastic fencing"Aerojipa" (skirt) consists of separate but identical elements - segments, cut and sewn from dense light fabric or film material. It is desirable that the fabric is water-repellent, does not harden in the cold and does not allow air to pass through.
I again used Vinyplan 4126 material, only with a lower density (240 g/m2), but domestic percale-type fabric is quite suitable.
The segments are slightly smaller in size than on the “balloonless” model. The pattern of the segment is simple, and you can sew it yourself, even by hand, or weld it with currents high frequency(TVS).
The segments are tied with the tongue of the lid to the seal of the balloon (two - at one end, while the knots are located inside under the skirt) along the entire perimeter of the Aeroamphibian. Two bottom corners The segments are suspended freely using nylon construction clamps from a steel cable with a diameter of 2 - 2.5 mm, encircling the lower part of the inner shell of the housing. In total, the skirt accommodates up to 60 segments. Steel rope with a diameter of 2.5 mm, it is attached to the body using clips, which in turn are attracted to the inner shell by petal rivets.
1 – scarf (material “Viniplan 4126”); 2 – tongue (material “Viniplan 4126”); 3 – overlay (Arctic fabric)
This fastening of the skirt segments does not significantly exceed the time required to replace a failed element of the flexible fence, compared to the previous design, when each was fastened separately. But as practice has shown, the skirt is operational even when up to 10% of the segments fail and their frequent replacement is not required.
1 – outer shell of the housing; 2 – inner shell of the body; 3 - overlay (fiberglass) 4 - strip (duralumin, strip 30x2); 5 – self-tapping screw; 6 – cylinder line; 7 – plastic bolt; 8 – balloon; 9 – cylinder apron; 10 – segment; 11 – lacing; 12 – clip; 13-clamp (plastic); 14-cable d2.5; 15-extension rivet; 16-eyelet
The propeller installation consists of an engine, a six-bladed propeller (fan) and a transmission.
Engine– RMZ-500 (analogue of Rotax 503) from the Taiga snowmobile. Produced by Russian Mechanics OJSC under license from the Austrian company Rotax. The engine is two-stroke, with a petal intake valve and forced air cooling. It has proven itself to be reliable, quite powerful (about 50 hp) and not heavy (about 37 kg), and most importantly, a relatively inexpensive unit. Fuel - AI-92 gasoline mixed with oil for two-stroke engines (for example, domestic MGD-14M). Average fuel consumption is 9 – 10 l/h. The engine is mounted in the rear part of the vehicle, on a motor mount attached to the bottom of the hull (or rather, to the under-engine wooden plate). The motorama has become taller. This is done for the convenience of cleaning the aft part of the cockpit from snow and ice that gets there through the sides and accumulates there and freezes when stopped.
1 – engine output shaft; 2 – driving toothed pulley (32 teeth); 3 – toothed belt; 4 – driven toothed pulley; 5 – M20 nut for axle fastening; 6 – spacer bushings (3 pcs.); 7 – bearing (2 pcs.); 8 – axis; 9 – screw bushing; 10 – rear strut support; 11 – front supra-engine support; 12 - front braced biped support (not shown in the drawing, see photo); 13 – outer cheek; 14 – inner cheek
The propeller is six-bladed, fixed pitch, with a diameter of 900 mm. (There was an attempt to install two five-bladed coaxial propellers, but it was unsuccessful). The screw bushing is made of cast aluminum. The blades are fiberglass, coated with gelcoat. The axis of the propeller hub was lengthened, although the same 6304 bearings remained on it. The axis was mounted on a stand above the engine and secured here with two spacers: a two-beam one in the front and a three-beam one in the rear. There is a mesh guard in front of the propeller, and rudder feathers at the rear.
The transmission of torque (rotation) from the engine output shaft to the propeller hub is carried out through a toothed belt with a gear ratio of 1:2.25 (the drive pulley has 32 teeth, and the driven pulley has 72).
The air flow from the propeller is distributed by a partition in the annular channel into two unequal parts (approximately 1:3). A smaller part of it goes under the bottom of the hull to create an air cushion, and a larger part goes to generate propulsive force (traction) for movement. A few words about the features of driving an amphibian, specifically about the start of movement. When the engine is running Idling the device remains motionless. As the number of its revolutions increases, the amphibian first rises above the supporting surface, and then begins to move forward at revolutions from 3200 - 3500 per minute. At this moment, it is important, especially when starting from the ground, that the pilot first lifts the rear part of the device: then the rear segments will not catch on anything, and the front segments will slip over uneven surfaces and obstacles.
1 – base ( steel sheet s6, 2 pcs.); 2 – portal stand (steel sheet s4.2 pcs.); 3 – jumper (steel sheet s10, 2 pcs.)
Control of the Aerojeep (changing the direction of movement) is carried out by aerodynamic rudders, hingedly attached to the annular channel. The steering wheel is deflected using a two-arm lever (motorcycle-type steering wheel) through an Italian Bowden cable going to one of the planes of the aerodynamic steering wheel. The other plane is connected to the first rigid rod. A carburetor throttle control lever or a “trigger” from a “Taiga” snowmobile is attached to the left handle of the lever.
1 – steering wheel; 2 – Bowden cable; 3 – unit for fastening the braid to the body (2 pcs.); 4 – Bowden braided cable; 5 – steering panel; 6 – lever; 7 – traction (rocking chair is not shown); 8 – bearing (4 pcs.)
Braking is carried out by “releasing the gas”. In this case, the air cushion disappears and the device rests with its body on the water (or skis on snow or soil) and stops due to friction.
Electrical equipment and instruments. The device is equipped battery, tachometer with hour meter, voltmeter, engine head temperature indicator, halogen headlights, ignition switch button and pin on the steering wheel, etc. The engine is started by an electric starter. It is possible to install any other devices.
The amphibious boat was named “Rybak-360”. It passed sea trials on the Volga: in 2010, at a rally of the Velkhod company in the village of Emmaus near Tver, in Nizhny Novgorod. At the request of Moskomsport, he participated in demonstration performances at the festival dedicated to Navy Day in Moscow on the Rowing Canal.
Aeroamphibian technical data:
Overall dimensions, mm:
length………………………………………………………………………………..3950
width…………………………………………………………………………………..2400
height……………………………………………………………………………….1380
Engine power, hp…………………………………………….52
Weight, kg……………………………………………………………………………….150
Load capacity, kg…………………………………………………………….370
Fuel capacity, l…………………………………………………………….12
Fuel consumption, l/h……………………………………………..9 - 10
Obstacles to be overcome:
rise, hail…………………………………………………………….20
wave, m………………………………………………………………………………0.5
Cruising speed, km/h:
by water……………………………………………………………………………….50
on the ground………………………………………………………………………………54
on ice……………………………………………………………………………….60
M. YAGUBOV Honorary Inventor of Moscow
Noticed a mistake? Select it and click Ctrl+Enter to let us know.
A hovercraft is a vehicle that can travel both on water and on land. It’s not at all difficult to make such a vehicle with your own hands.
This is a device that combines the functions of a car and a boat. The result was a hovercraft (hovercraft), which has unique cross-country characteristics, without loss of speed when moving through water due to the fact that the hull of the vessel does not move through the water, but above its surface. This made it possible to move through the water much faster, due to the fact that the friction force of the water masses does not provide any resistance.
Although the hovercraft has a number of advantages, its field of application is not so widespread. The fact is that this device cannot move on any surface without any problems. It requires soft sandy or soil soil, without stones or other obstacles. The presence of asphalt and other hard bases can render the bottom of the vessel, which creates an air cushion when moving, unusable. In this regard, “hovercrafts” are used where you need to sail more and drive less. If on the contrary, then it is better to use the services of an amphibious vehicle with wheels. Ideal conditions their application is in difficult to pass swampy places where, except for a hovercraft (hovercraft), no other vehicle can pass. Therefore, hovercrafts have not become so widespread, although similar transport is used by rescuers in some countries, such as Canada, for example. According to some reports, SVPs are in service with NATO countries.
How to purchase such a vehicle or how to make it yourself?
Hovercraft is an expensive type of transport, the average price of which reaches 700 thousand rubles. Scooter-type transport costs 10 times less. But at the same time, one should take into account the fact that factory-made transport is always different best quality, compared to homemade products. And the reliability of the vehicle is higher. In addition, factory models are accompanied by factory warranties, which cannot be said about structures assembled in garages.
Factory models have always been focused on a narrowly professional area associated with either fishing, or hunting, or special services. As for homemade hovercraft, they are extremely rare and there are reasons for this.
These reasons include:
- Enough high cost, as well as expensive maintenance. The main elements of the device wear out quickly, which requires their replacement. Moreover, each such repair will cost a pretty penny. Only a rich person will afford to buy such a device, and even then he will think again whether it is worth getting involved with it. The fact is that such workshops are as rare as the vehicle itself. Therefore, it is more profitable to purchase a jet ski or ATV for moving on water.
- The operating product creates a lot of noise, so you can only move around with headphones.
- When moving against the wind, the speed drops significantly and fuel consumption increases significantly. Therefore, homemade hovercraft is more of a demonstration of one’s professional abilities. You not only need to be able to operate a vessel, but also be able to repair it, without significant expenditure of funds.
DIY SVP manufacturing process
Firstly, assembling a good hovercraft at home is not so easy. To do this you need to have the opportunity, desire and professional skills. A technical education wouldn't hurt either. If the last condition is absent, then it is better to refuse to build the apparatus, otherwise you may crash on it during the first test.
All work begins with sketches, which are then transformed into working drawings. When creating sketches, you should remember that this device should be as streamlined as possible so as not to create unnecessary resistance when moving. At this stage, one should take into account the fact that this is practically an aerial vehicle, although it is very low to the surface of the earth. If all conditions are taken into account, then you can begin to develop drawings.
The figure shows a sketch of the SVP of the Canadian Rescue Service.
Technical data of the device
As a rule, all hovercraft are capable of achieving decent speeds that no boat can achieve. This is when you consider that the boat and hovercraft have the same mass and engine power.
At the same time, the proposed model of a single-seat hovercraft is designed for a pilot weighing from 100 to 120 kilograms.
As for driving a vehicle, it is quite specific and in comparison with driving a conventional motor boat doesn't fit in at all. The specificity is associated not only with the presence of high speed, but also with the method of movement.
The main nuance is related to the fact that when turning, especially at high speeds, the ship skids strongly. To minimize this factor, you need to lean to the side when turning. But these are short-term difficulties. Over time, the control technique is mastered and the hovercraft can demonstrate miracles of maneuverability.
What materials are needed?
Basically you will need plywood, foam plastic and a special construction kit from Universal Hovercraft, which includes everything you need to assemble the vehicle yourself. The kit includes insulation, screws, air cushion fabric, special glue and more. This set can be ordered on the official website by paying 500 bucks for it. The kit also includes several variants of drawings for assembling the SVP apparatus.
Since the drawings are already available, the shape of the vessel should be linked to the finished drawing. But if you have a technical background, then, most likely, a ship will be built that is not similar to any of the options.
The bottom of the vessel is made of foam plastic, 5-7 cm thick. If you need a device to transport more than one passenger, then another sheet of foam plastic is attached to the bottom. After this, two holes are made in the bottom: one is intended for air flow, and the second is to provide the pillow with air. Holes are cut using an electric jigsaw.
On next stage seal the lower part of the vehicle from moisture. To do this, take fiberglass and glue it to the foam using epoxy glue. At the same time, unevenness may form on the surface and air bubbles. To get rid of them, the surface is covered with polyethylene and a blanket on top. Then, another layer of film is placed on the blanket, after which it is fixed to the base with tape. It is better to blow the air out of this “sandwich” using a vacuum cleaner. After 2 or 3 hours, the epoxy resin will harden and the bottom will be ready for further work.
The top of the body can have any shape, but take into account the laws of aerodynamics. After this, they begin to attach the pillow. The most important thing is that air enters it without loss.
The pipe for the motor should be made of styrofoam. The main thing here is to guess the size: if the pipe is too large, then you will not get the traction that is necessary to lift the hovercraft. Then you should pay attention to mounting the motor. The motor holder is a kind of stool consisting of 3 legs attached to the bottom. The engine is installed on top of this “stool”.
What engine do you need?
There are two options: the first option is to use an engine from Universal Hovercraft or use any suitable engine. This could be a chainsaw engine, the power of which is quite enough for a homemade device. If you want to get a more powerful device, then you should take a more powerful engine.
It is advisable to use factory-made blades (those included in the kit), since they require careful balancing and this is quite difficult to do at home. If this is not done, the unbalanced blades will destroy the entire engine.
How reliable can a hovercraft be?
As practice shows, factory hovercraft (hovercraft) have to be repaired about once every six months. But these problems are insignificant and do not require serious costs. Basically, the airbag and air supply system fail. In fact, the likelihood is that homemade device will fall apart during operation, it is very small if the “hovercraft” is assembled competently and correctly. For this to happen, you need to run into some obstacle at high speed. Despite this, the air cushion is still able to protect the device from serious damage.
Rescuers working on similar devices in Canada repair them quickly and competently. As for the pillow, it can actually be repaired in a regular garage.
Such a model will be reliable if:
- The materials and parts used were of good quality.
- The device has a new engine installed.
- All connections and fastenings are made reliably.
- The manufacturer has all the necessary skills.
If the SVP is made as a toy for a child, then in this case it is desirable that the data of a good designer be present. Although this is not an indicator for putting children behind the wheel of this vehicle. This is not a car or a boat. Operating a hovercraft is not as easy as it seems.
Taking this factor into account, you need to immediately begin manufacturing a two-seater version in order to control the actions of the one who will sit behind the wheel.